JP2001346162A - Multiplexed stream converter and method, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recorder that causes no mismatching with other data in the case of reproducing a video stream that is recorded after it is re-encoded. SOLUTION: A demultiplexer 12 and an analysis section 13 receive a transport stream received by the recorder 10. The analysis section 13 outputs information of a stream other than the video stream to a coding controller section 18. The coding controller section 18 controls encoding by an encoder 15 on the basis of received information and outputs video coded control information to a multimedia coding data encoder 20. The multimedia coding data encoder 20 alters multimedia coded data from the demultiplexer 12 into data not causing mismatching between the video data and other data at a reproduction side on the basis of the video coding section control information and outputs the altered data to a multiplexer 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplexed stream conversion apparatus and method, and a recording medium, and more particularly to a multiplexed stream conversion apparatus and method suitable for use in an apparatus for recording a video stream by re-encoding. It relates to a recording medium.

[0002]

2. Description of the Related Art European DVB (Digital Video Broadcast)
cast), US DTV (Digital Television) broadcast, Japanese BS (Broadcast Satellite) digital broadcast, and other digital television broadcasts.
Picture Expert Group) 2 transport streams are used. The transport stream is a stream in which transport packets are continuous, and the transport packets are, for example, packetized video data and audio data. The data length of one transport packet is 188 bytes.

[0003] Unlike digital television broadcasting, digital television broadcasting can provide a service to which multimedia encoded data is added. In this service, data such as video data, audio data, character / graphic data, and still image data is transmitted in association with multimedia encoded data. For example, in the case of BS digital broadcasting in Japan, multimedia encoded data is XML (Extensible Markup Lan).
guage) based coding scheme is used. For details, see ARIB STD-B24 Data Coding and tra
nsmission Specification for digital broadcasting
(ARIB STD-B24 data broadcast encoding and transmission schemes in digital broadcasting).

[0004] Data such as video data, audio data, character / graphic data, and still image data are each transmitted as a transport packet.

Referring to FIG. 1, an example of combining data and multimedia screens transmitted and received between a transmitting side and a receiving side will be described. As shown in FIG. 1A, the transmitting side transmits video data, character graphic data for displaying buttons A to C, character data for displaying characters such as “XYZABC. The multimedia encoded data for association is transmitted to the receiving side. The transmitting side is a television broadcasting station or the like,
Here, a recording device (recording side) for receiving and recording data transmitted from a broadcasting station is also included.
Is included in the data output from the recording device.

[0006] Multimedia encoded data includes video data, character / graphic data, and data that can be combined and displayed on the receiving side. That is, as shown in FIG. 1B, the multimedia encoded data has a size (plane_height, a size of a multimedia plane (a display area of an image such as a television receiver)).
plane_width) and video display size (video_height, v
ideo_width), video data, character / graphic data, and data related to the display position of the video, character / graphic, and character displayed by the respective data of the character data.

On the receiving side, video data, character / graphic data, and character data are respectively processed based on the multimedia encoded data, and as shown in FIG.
An image is displayed based on each data.

When the user operates the button A, for example, from the screen displayed in this manner, information corresponding to the operation is displayed in a service such as displaying a video portion, or displayed in a lower portion of the screen. It is possible to receive a service such as obtaining information on a matter displayed in a video portion from character data that is present.

[0009]

If a television program of a transport stream broadcasted by digital television broadcasting is directly recorded on a recording medium or the like on the receiving side, the image quality and audio quality are not degraded at all. It is possible to record. When recording a program as long as possible on a limited-capacity recording medium, assuming that image quality will deteriorate, the received video stream is decoded once and then re-encoded to reduce the bit rate. Such processing is required.

When a video stream of a television program to which multimedia encoded data is added is re-encoded for recording at a lower bit rate as described above, when an image is sub-sampled to change an image frame, However, there is a problem that a mismatch may occur in the relationship between the video stream obtained by re-encoding and the multimedia encoded data. An example of the mismatch will be described with reference to FIG.

As shown in FIG. 2A, when the data is re-encoded and recorded on the transmitting side (recording side), it is converted into an image frame smaller than the original video image frame and recorded. I'm done. As a result, as shown in FIG. 2B, the display size and the display position of the video are changed on the receiving side (reproducing side), and the display screen intended by the transmitting side (data before re-encoding is used). (Display screen to be displayed).

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is an object of the present invention to change multimedia encoded data on the recording side so as to prevent inconsistency when re-encoding and recording a video stream. Accordingly, it is an object of the present invention to prevent the occurrence of inconsistency such as a reduction in the image frame of a video on the reproduction side.

[0013]

According to a first aspect of the present invention, there is provided a multiplexed stream converter for separating at least a video stream and multimedia encoded data from a first multiplexed stream. First converting means for converting the encoding parameters of the video stream, and second converting means for converting the multimedia encoded data separated by the separating means based on the conversion contents of the encoding parameters in the first converting means. Means, and multiplexing means for multiplexing at least the video stream converted by the first conversion means and the multimedia encoded data converted by the second conversion means to generate a second multiplexed stream. It is characterized by the following.

[0014] The first converting means may convert a parameter of an image frame of a video stream.

[0015] The first converting means may include at least processing for decoding the video stream separated by the separating means and encoding the decoded video stream.

According to a fourth aspect of the present invention, there is provided a method for converting a multiplexed stream, comprising: a separating step of separating at least a video stream and multimedia encoded data from the first multiplexed stream; A first conversion step of converting an encoding parameter, and a second conversion of converting multimedia encoded data separated in the separation step based on the conversion content of the encoding parameter in the processing of the first conversion step. Multiplexing step: multiplexing at least the video stream converted in the processing of the first conversion step and the multimedia encoded data converted in the processing of the second conversion step to generate a second multiplexed stream And a step.

According to a fifth aspect of the present invention, there is provided a recording medium program comprising: a separating step of separating at least a video stream and multimedia encoded data from a first multiplexed stream; and a code of the video stream separated by the processing of the separating step. First converting step of converting the encoding parameter, and second converting step of converting the multimedia encoded data separated by the processing of the separating step based on the contents of the conversion of the encoding parameter in the processing of the first converting step And a multiplexing step of multiplexing at least the video stream converted in the processing of the first conversion step and the multimedia encoded data converted in the processing of the second conversion step to generate a second multiplexed stream. And characterized in that:

[0018] In the multiplexed stream converter according to the first aspect, the multiplexed stream conversion method according to the fourth aspect, and the recording medium according to the fifth aspect, at least a video stream from the first multiplexed stream can be obtained. The multimedia coded data is separated, the coding parameters of the video stream are converted, and the multimedia coded data is converted based on the conversion contents of the coding parameters.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram showing a configuration of an embodiment of a recording apparatus to which the present invention is applied. The transport stream received by an antenna (not shown) is input to the selector 10. Terminal 11
A program number (channel number) specified by the user is input. The selector 10 extracts the selected program from the transport stream based on the program number,
Output a partial transport stream. The partial transport stream is input to the demultiplexer 12 and the analysis unit 13.

The transport stream input to the demultiplexer 12 is separated into a video stream, other streams (streams composed of data such as audio, still picture, character and graphic data), and multimedia encoded data. . The separated video stream is sent to the decoder 14, the other streams are sent to the multiplexer 16, and the multimedia encoded data is sent to the decoder 14.
The data is output to the multimedia encoded data encoder 20, respectively. The demultiplexer 12 also outputs to the multiplexer 16 transport packets other than video and information on the output timing of those transport packets in the input transport stream.

The decoder 14 performs a decoding process on the input video stream based on a predetermined decoding method, for example, the MPEG2 method, and outputs video data to the encoder 15. In addition, the decoder 14 outputs the stream information of the video stream obtained at the time of decoding to the encoding controller 18.

On the other hand, the analysis unit 13 analyzes the input transport stream to obtain stream information other than video, for example, information such as a bit rate, and outputs the information to the encoding controller unit 18. The encoding controller 18 receives stream information other than video output from the analyzer 13, video stream information output from the decoder 14, and the recording bit rate of the stream via the terminal 19. The encoding controller unit 17 sets conditions for encoding video data performed by the encoder 15 from these data, and outputs the set conditions (encoding control information) to the encoder 15.

For example, the value obtained by subtracting the total value of the bit rates of the streams other than the video (the data input from the analyzing unit 13) from the recording bit rate of the stream (the data input from the terminal 19) is the video data. Set the bit rate to be assigned to the encoding, set the encoding control information such as bit rate and picture frame so that the optimal image quality is obtained at the set bit rate, and set the encoding control information to the encoder. 15 is output.

The encoder 15 encodes the video data output from the decoder 14 based on the encoding control information output from the encoding controller 18 (for example,
(Encoding based on the MPEG2 system) and outputs the result to the multiplexer 16. The multiplexer 16 also receives multimedia encoded data output from the multimedia encoded data encoder 20.

Multimedia encoded data encoder 2
0 changes the content of the multimedia encoded data from the demultiplexer 12 based on the video encoding control information from the encoding controller 18. In other words, even when the image frame size is changed due to the re-encoding of the video stream, the multimedia coded data encoder 20 performs the processing on the multimedia plane (for example, a display area of a television receiver). ,
The input multimedia encoded data is encoded so that the display position and display size of the video are the same as the screen intended by the transmission side (the screen obtained from the data before re-encoding). Change based on control information.

For example, referring to FIG. 4, the horizontal and vertical sizes of the picture frame of the video transmitted from the transmission side are set to one, and the data relating to the enlargement ratio of the multimedia encoded data is set to one. In this case, it is assumed that the horizontal and vertical sizes of the video image frame are changed to 0.5 times by re-encoding. If the data relating to the enlargement ratio of the multimedia encoded data is recorded on the recording medium 22 with the data being kept at 1, the display size (image frame) of the video is smaller than the size intended by the transmission side (in this case, , 0.5 times the size). Therefore, the enlargement ratio of the multimedia encoded data is changed to twice, and the multimedia encoded data with the changed enlargement ratio is used and reproduced on the receiving side, so that the video display size intended by the transmission side is obtained. Is displayed with.

The multiplexer 16 converts the video stream from the encoder 15, the transport stream packet other than video from the demultiplexer 12, information on its appearance timing, and the multimedia encoded data from the multimedia encoded data encoder 20. The video stream, the transport stream packet other than the video, and the multimedia encoded data are multiplexed based on the information on the appearance timing, and the multiplexed data is output to the arrival time stamp adding unit 17 as a transport stream. .

The arrival time stamp adding unit 17
A header including an arrival time stamp is added to each transport stream packet of the input transport stream, and the source packet is
Output to The arrival time stamp is information indicating the timing at which a transport stream packet appears in a transport stream. The writing unit 21 converts the input source packet stream including the continuous source packets into a file,
To record. Note that the recording medium 22 may be any medium.

In this way, even if the picture frame or the like of the video is changed by re-encoding, the multimedia encoded data is also changed so as to correspond to the change, and it is converted into a source packet stream file together with the video stream and the like. By recording, it is possible to prevent the occurrence of inconsistency in the relationship between the video stream and the multimedia coded data.
In, the same display position and display size of the video on the multimedia plane as intended by the transmission side are presented.

In the present embodiment, as an example of a method for re-encoding a video, an example in which an input video stream is decoded and a decoded image is encoded has been described. However, the present invention is not limited to such a method. The video stream may be converted on the DCT area to convert coding parameters such as image frames.

Next, reproduction of the source packet stream file recorded on the recording medium 22 will be described. FIG. 5 is a diagram showing the configuration of the playback device. The source packet stream file recorded on the recording medium 22 is
It is read by the reading unit 31. The source packet stream read by the reading unit 31 is output to the arrival time stamp separation unit 32.

The arrival time stamp separation unit 32
A reference clock is built-in, and the value of the arrival time stamp added to the source packet of the input source packet stream is compared with the reference clock, and when both values are equal, the values become equal. From the source packet with the given arrival timestamp
The arrival time stamp is removed and output to the demultiplexer 33 as a transport stream.

The demultiplexer 33 converts the input transport stream into a video audio stream,
The stream is separated into multimedia encoded data and a stream composed of data such as character figures / characters / still images. Of the separated data, the video / audio stream is sent to the decoder 34, the multimedia encoded data is sent to the synthesizing unit 36, and the data stream such as character / graphic / character / still image is sent to the character / graphic / still image decoder 35. ,
Each is output.

The decoder 34 separates the input video / audio stream into a video signal and an audio signal, and outputs the audio signal to an audio reproducing device (not shown) and the video signal to the synthesizing unit 36, respectively. The character / graphic / still image decoder 35 decodes an input data stream of character / graphics, characters, still images, etc., and outputs decoded data such as character / graphics data, character data, still image data to the synthesizing unit 36. I do.

The synthesizing unit 36 includes video data from the decoder 34, multimedia encoded data output from the demultiplexer 33, and character figures / characters / still images output from the character / picture / still picture decoder 35. Is input. The synthesizing unit 36 synthesizes video data and character / graphic data on a multimedia plane based on the input multimedia encoded data, and outputs a video signal to a television receiver or the like (not shown) as a display device. I do.

As described above, when recording a television broadcast program to which multimedia encoded data is added, when the size of an image frame or the like is changed by re-encoding the video stream of the program, By changing the multimedia encoded data correspondingly, the display position and the display size of the video on the multimedia plane on the playback side are the same as those intended by the transmission side (the screen before re-encoding). The screen obtained from the data) is reproduced.

Further, in the recording apparatus, in order to change the multimedia encoded data, the reproducing apparatus can use a conventional reproducing apparatus without any change.

In this embodiment, the case of the transport stream has been described. However, the present invention is not limited to this, and can be applied to a multiplexed stream such as a program stream.

The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, it is possible to execute various functions by installing a computer in which the programs constituting the software are embedded in dedicated hardware, or by installing various programs For example, it is installed from a recording medium to a general-purpose personal computer or the like.

As shown in FIG. 9, this recording medium is a magnetic disk 121 (including a floppy disk) on which the program is recorded, which is distributed separately from the computer to provide the program to the user, and an optical disk 12
2 (CD-ROM (Compact Disk-Read Only Memory), DVD
(Including a Digital Versatile Disk), a magneto-optical disk 123 (including an MD (Mini-Disk)), or a packaged medium including a semiconductor memory 124, as well as a user installed in a computer in advance. Is stored in the program
The hard disk drive includes the ROM 102 and the storage unit 108.

In this specification, the steps of describing a program provided by a medium may be performed in a chronological order according to the described order. Alternatively, it also includes individually executed processing.

[0042]

As described above, in the multiplexed stream conversion apparatus according to the first aspect, the multiplexed stream conversion method according to the fourth aspect, and the recording medium according to the fifth aspect, the first multiplexing is performed. At least the video stream and the multimedia encoded data are separated from the stream, the encoding parameters of the video stream are converted, and the multimedia encoded data is converted based on the conversion contents of the encoding parameters. On the side, it is possible to prevent a mismatch between the video stream and the multimedia encoded data.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a display screen based on multimedia encoded information.

FIG. 2 is a diagram illustrating a mismatch that occurs when re-encoding is performed.

FIG. 3 is a diagram illustrating a configuration of an embodiment of a recording apparatus to which the present invention has been applied.

FIG. 4 is a diagram illustrating a change of multimedia encoded data.

FIG. 5 is a diagram showing a configuration of an embodiment of a reproducing apparatus to which the present invention is applied.

FIG. 6 is a diagram illustrating a medium.

[Explanation of symbols]

Reference Signs List 10 recording device, 11 terminals, 12 demultiplexers, 13 analyzers, 14 decoders, 15 encoders, 16 multiplexers, 17 arrival time stamp adding units, 18 encoding controller units, 19 terminals, 20 multimedia encoded data encoders, 21 writing Part, 22 recording media,
Reference Signs List 30 playback device, 31 reading unit, 32 arrival time stamp separation unit, 33 demultiplexer, 34 AV decoder, 35 character figure / still image decoder, 36 synthesis unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C053 FA05 FA20 GA06 GB21 JA01 JA16 5C059 MA00 PP20 RB02 RB10 SS02 SS11 TA16 TA80 TB13 TC24 TC25 5J064 AA05 BA01 BA11 BB10 BC01 BC02 BC25 BD02 BD03

Claims (5)

[Claims] 1. A multiplexed stream converter for generating a second multiplexed stream from a first multiplexed stream, comprising: separating means for separating at least a video stream and multimedia encoded data from the first multiplexed stream. A first conversion unit for converting an encoding parameter of a video stream separated by the separation unit; and a multimedia separated by the separation unit based on conversion contents of the coding parameter in the first conversion unit. Second converting means for converting encoded data; and multiplexing at least the video stream converted by the first converting means and the multimedia encoded data converted by the second converting means; Multiplexing means for generating a multiplexed stream of Conversion apparatus. 2. The multiplexed stream converter according to claim 1, wherein the first converter converts a parameter of an image frame of the video stream. 3. The apparatus according to claim 1, wherein the first conversion unit includes at least a process of decoding the video stream separated by the separation unit and encoding the decoded video stream. Multiplexed stream converter. 4. A multiplexed stream conversion method for a multiplexed stream converter for generating a second multiplexed stream from a first multiplexed stream, wherein at least a video stream and multimedia coding are performed from the first multiplexed stream. A separating step of separating data; a first converting step of converting an encoding parameter of the video stream separated by the processing of the separating step; and a converting step of converting the encoding parameter in the processing of the first converting step. A second converting step of converting the multimedia encoded data separated by the processing of the separating step; and a video stream converted by at least the processing of the first converting step and the processing of the second converting step. Multiplexing the converted multimedia encoded data, Multiplexed stream conversion method characterized in that it comprises a multiplexing step of generating the redundant stream. 5. A multiplexed stream conversion program for a multiplexed stream converter for generating a second multiplexed stream from a first multiplexed stream, the program comprising at least a video stream from the first multiplexed stream. A separating step of separating multimedia encoded data; a first converting step of converting a coding parameter of a video stream separated by the processing of the separating step; and a converting step of coding parameters in the processing of the first converting step. A second conversion step of converting the multimedia encoded data separated in the processing of the separation step based on the conversion content; and a video stream converted in at least the processing of the first conversion step and the second conversion. Multiplex the multimedia encoded data converted in the process of step, Serial second recording medium from which a computer readable program is recorded, characterized in that it comprises a multiplexing step of generating a multiplexed stream.